Lower atmospheric wind observation by L-band Doppler radar in Thailand

摘要

The study of low atmospheric boundary layer wind by wind profiler radar is the aim of this present. The L-band Doppler radar used as the meteorological equipment using operating frequency 1357.5 MHz. The transmitter radiates the pulse signal of peak power 1 kW through the upper air. The single parabolic antenna is steering into three directions, vertical, north and east respectively. This radar received the echo scattered back by the irregularity of atmospheric refractivity along the beam. The Doppler shift frequency deviates by the movement of turbulent are used to calculate the wind velocity and wind direction. The observation height starts from 150 meters to 4 km. The diurnal and seasonal wind had been observed for six years continuously. It shows the variation of wind in each year, which correspond to Asia monsoon, Northeastern monsoon and Southwestern Monsoon. While the radio sonde, which operates by radio propagation technique is used for wind measurements too. The comparisons of both systems are present in correlation method.